Inductance system



April 21, 1931. POWELL INDUCTANCE SYSTEM Filed June 11,1928

3 Sheets-Sheet 1 II II. 0 kn$ 'H m\ d m 9 r H :5 w m a N o 0 m b m f H 0 v n 0 0 W m TH a X H H n M i INVENTOR. Edwz'ra awezz,

A TORNEY April 21, 1931- E. 1.. POWELL 1,801,455

INDUCTANCE SYSTEM Filed June 11, 1928 3 Sheets- Sheet 2 I N VEN TOR.

Elwin l PmaeZZ,

BY cum sL 2 13i) April 21, E. L. POWELL 1,801,455

INDUCTANCE SYSTEM Filed June 11, 1928 3 Sheets-Sheet 3 Isair- 8 I N VEN TOR.

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- A TORNEY Patented Apr. 21, 1931 UNITED STATES PATENT OFFICE IN DUOTAN CE SYSTEM.

Application filed June 11,

cifically to radio signaling systems.

Another object o vide an efiicient inductance system, that may be employed to cover a wide band of frequencies, contained 15 compact as is consistent with efficiency.

A further ob ect of my invention is to provide an inductance unit which will cover a wide band of frequencies without the use of interchangeable coils and troublesome balancing of the circuits when interchangeable coils are employed.

better understanding of my invention can be had by referring to the specification which follows and to the accompanying drawings, in which: 1

Figure 1 is a diagrammatic circuit arrangement illustrating the inductance units and their application to a space radio s stem; Fig. 2 illustrates a rear view of the 1nductance unit embodyin my invention ig. 3. is an illustration 0 -a cross-sectional view of the inductance unit shown partially in side elevation; Fig. 4 is a side elevation of the inductance unit of my'invention; Fig. 5 illustrates the connections and relative inductance value at one adjustment of the inductance and couplin unit of my invention; Fig. 6 illustrates t e same circuit with a lower induc, ment of the inductance unit of my invention; Figs. 9 and 10 illustrate other and-circuit arrangements obtained by further adjustments of the inductance umt of my invention.

ferring to the drawings in detail the inductances are supported with respect to a panel structure 11 by means of pedestal members 19 extend' perpendicular-to the panel and carrying tfie frame structure for tance value obtained by the second adjustt my invention is to proin a unit as small and of my mvention I plates 3 1928. Serial No. 284,608.

the inductance. The frame structure comprises concentric tubular members 1 and 2, supported in grooves in the end plates 3 and 4 and secured therein by suitable screws 14. A pair of semi-circular conductor members in the form of sectors 5 are mounted g on the lnterior of the insulated end plate 3 he panel structure 11 carrying a bearby means of knob 16 panel 29. Insulated The end of the shaft 28 represented at 31 to receive the A resonating circuit which consists of a variable air condenser connected in parallel with a built-in step ed inductance system is shown in Fig. 1. his inductance value is controlled by a multi-position switch, the

equencies covered in the range of the Va riable condenser for each step corresponding 0 those secured with interchangeable receiver coils. The structure I employ inductance unit makes possible the of the required inductance values various steps without serious losses from unused turns at any frequency within a desired range. Figs. 2 and 3 show the structural arrangement of two fluted winding forms 1 and. 2, one contained within the other, concentrically supported between two end and 4 which carry the contacts 25 with the antenna coupling and sectors 5 .of the switching mechanism. The outer form 1 carries, in addition to a coupling coil 6, a winding 7 tapped for steps 1 and 2 of the switching mechanism; the natural frequency of the dead end turns when step 2 is 1n use being considerably higher than the maximum frequency to which the circuit will resonate, hence no serious absorption occurs. The inner form 2 carries a winding 8 which is tapped to the switching mechanism for steps 3, 4, 5 and 6. Resonant absorption by coil 1 when workingon steps 3, 4, 5 and 6 is prevented by its inclusion in the circuit as a shunt around the active turns of the inner coil as shown in Figs. 7 8, 9 and 10. These combinations are automatically controlled by a double contacting laminated switch arm 9 mounted on an insulated shaft 10 inside the inner coil form 2. The active parts circuit are thus insulated bearing clicker system parts of the control mechanism which are mounted on the sub-panel 1 1 of the unit, reducing the parasitic capacities to a low minimum. oil windings 7 and '8 are wound on fluted forms 1 and 2 thus providing a low loss in the winding forms. The small contact of the form and winding as shown in Fig. 4is adequate to hold the winding in position on the form.

Many advantages have been noted from the use of this inductance system as compared directly with separate coils for each frequency band. The stepped inductance and coupling unit when connected as the input circuit of a' three element vacuum tube winding inserted in the plate circuit for tickler feed back produces oscillationsover the greater part of the frequency range. It is to be understood that the inductance and coupling unit of my invention may be substituted for other type coils in both radio frequency amplifier and receiver circuits and in combination with equipment not referred to in this specification and that its application is therefore not limited to the circuit arrangement shown herein.

What I claim and desire to secure by Letters Patent of the United States is as follows: .1

1. An inductance and coupling unit comprising in combination a plurality of coil forms positioned one within the other, a plurality of coil windings positioned on sai coil forms, end plates supporting said coil forms, a multi-contact switching mechanism supported between and by said end plates and contact members connected to said coil windings.

2. In an inductance and coupling unit a plurality of windings arranged'on a plural ity of cylindrical coil forms, said coil forms concentrically supported between two end from the switch 12 and other metallic d lated nection is provided between plates, a switching mechanism supported between and by said end plates and within said coil forms, a pluralit of contact members carried by said en plates, electrical connections between said contact mem rsand said windings, means for adjusting said switching mechanism with respect to said contact members, and said electrical connection arranged with respect to-said coil windings whereby said coil windings may be selectively connected in a plurality of multiple circuit arrangements by the ad ustment of said switching mechanism. 7

3. In an inductance and coupling unit comprising in combination concentric tubular members having windings thereon, said tubular members supported by two end plates, one of said end plates having curved conductor members, the other of said end 1 plates having contacts extended interiorly of said tubular members and electrically connected to the respective windings on said tubular members, a shaft extending through said end plates and having a contactor arm thereon, and said contactor adapted to simultaneously make contact with said contacts and conductor members.

4. In aninductance and coupling unit the combination of concentric tubular members having inductance windings thereon, sai tubular member su ported by two end plates, a pair of con uctor members in the form of sectors mounted on the interior of one of said end plates, a set of contacts mounted on the other said end plate an extending interiorly of said tubular member, electrical connections between said wmdings and. said contacts, a panel structure supported by end plates, contacts carried by one of said end plates said tubular members 1 having windings thereon electrically connected to said contacts, a panel structure supporting said tubular members-and said end plates, a bearing in one of said end plates and in' said panel structure, an insushaft member extending through said bearings, a contactor member mounted on the portion of said shaft member extending through said tubular member, curved conductor members mounted on one of said end plates and means provided to rotate said shaft member whereby an electrical consaid contacts and said conductor members-to provide a plurality'of inductance values predetermined by the electrical connections between said coil windings and said contacts.

forms arranged concentrically one within the other, a plurality of windings on said coil forms, a common support for said coil orms, a switching mechanism arranged on said common support, groups of contact members carried by said common support, a plurality of connections between each of said coil windings, groups of contact members and said switching mechanism, and external connections thereto whereby one of said coil windings, other of said coil windings, and a parallel connection of said coil windings may be selectively associated with an external circuit.

EDWIN L. POWELL. 

